In an image pickup apparatus such as a digital camera (a digital still camera), a diaphragm (an iris) that performs mechanical dimming operation (light quantity adjustment) is typically provided as a dimming device adjusting light quantity of image pickup light. Moreover, recently, as an alternative to such a mechanical diaphragm, an electrical dimming device (a liquid crystal dimming device) using a guest-host (GH) type liquid crystal that contains dichroic pigment has been proposed (for example, refer to PTL 1).